I. Field of the Invention
This invention relates generally to a novel printing method, and more specifically to a method of imprinting characters on an adhesive bearing tape medium in such a fashion that the ink penetrates beneath any antiblocking layer which may be present on the surface of the medium opposite to the one on which the adhesive is coated. As such, following the printing step, the tape may be rolled and subsequently unrolled for dispensing without smearing or obliterating the printed characters.
II. Description of the Prior Art
In preparing labels and the like, it is desirable that one be able to imprint a predetermined message or other information on an adhesive bearing tape, which tape can be rerolled following printing so that the ultimate user may draw a preprinted strip of tape from the roll and use it as a label. In order to facilitate the unrolling of an adhesive bearing ribbon or tape, it is common practice to employ a suitable antiblocking layer on the surface of the tape which is opposite to the one on which the adhesive layer is coated. This antiblocking layer is typically a silicone compound which prevents the adhesive surface from strongly attaching itself to the non-adhesive side of the tape when rolled. While the antiblocking layer facilitates the unrolling and dispensing of the adhesive tape, it does not provide a convenient surface on which to imprint alphanumeric or other characters with ink. The smooth, non-porous antiblocking layer does not absorb conventional printing inks and as a result, when the preprinted adhesive tape is dispensed from the roll, the ink material is often smeared or obliterated or removed by the adhesive layer.
In accordance with the teachings of the present invention, I provide a method whereby pressure sensitive adhesive tapes having an antiblocking layer on one surface and an adhesive layer on the opposite surface may be drawn off from a roll, printed with characters and rerolled prior to the end use of the tape as a label. The novel method employs the use of a printing plate having the desired characters defined by pin-like projections extending from the surface thereof. The pin-like projections defining the characters to be printed are next coated with a suitable printing ink and then brought in contact with the antiblocking layer surface of the adhesive tape with sufficient force that the pin-like projections penetrate through the antiblocking layer and deposit the ink within the tape media in a manner somewhat analogous to tattooing. Following the printing step, the tape may be rerolled such that the adhesive surface cooperates with the antiblocking surface on an adjacent layer. Because of the manner in which the ink is injected through the antiblocking layer, this antiblocking layer is not destroyed and it continues to serve its purpose of facilitating the subsequent unrolling of the tape from the roll by the ultimate user.
The closest prior art of which I am aware relates to so-called check protectors of the type disclosed in the Peters Pat. No. 1,480,690 and the Dauley et al U.S. Pat. No. 1,448,994. In each of these arrangements a type wheel having projections for perforating paper are passed over an inking roller and then brought in contact with a paper medium such as a bank check. The purpose, of course, is to inhibit subsequent alteration of the information printed on the check blank. Because of the manner in which the paper is perforated and inked, attempts at erasure will destroy the paper.